In a small bowl, stir together the soy sauce, mirin, orange juice, miso paste, and sugar.
In a large skillet or a wok, heat half the oil over high heat until it’s very hot. Add the sugar snap peas and sauté for 2 minutes, until just barely crisp-tender. Stir in the scallions and sauté for 1 more minute. Transfer the vegetables to a serving bowl.
Return the skillet to the heat and add the remaining oil. Add the shrimp and sauté for about 2 minutes until the shrimp turns pink. Return the vegetables to the pan, toss everything around to combine, and then add the sauce and cook, stirring, for another minute until everything is just cooked and the sauce coats everything nicely. Turn the stir fry back into the serving bowl and serve with rice or noodles. You can also place the cooked rice or noodles in the serving bowl while the stir fry finishes cooking, and then spoon the stir fry over the starch in the bowl, or in the case of noddles add them into the pan with the stir fry and the end and toss until combined and warm.) Serve immediately.
Notes
Mirin is a slightly sweet cooking wine made from rice, often used in Asian cooking. It’s basically sake with more sweetness and less alcohol. Miso is a fermented soybean paste that comes in a variety of colors, flavors, and strengths. Start with the lighter colors, such as white or yellow, which are milder, and work your way deeper.